Can this be changed? I mean, is it possible for the AOpen to collect data for 1 ECC block instead of 32 ECC blocks? If not, I guess we have to adjust our reference once and for all and forget about comparing with K's Probe scans. Unless ...

Could you implement a checkbox/switch that will adjust the results by dividing PI by 4 and PIF by 32? Wouldn't this be an easy/awesome way to make the scans comparable after all?

Cheers,
Peter

If this were the case then the scan would simply be a higher proportion of the Liteon scan and the graph would follow the same shape, just higher. This is not the case. Also the initial error rate when the drive is at a low speed is not a 4 time multiple of the correct error rate but is closer to 10 to 15 times the correct PI error. While it may change and become true when the speed is reduced I will need to see it before I accept it. So far it is theory, logical, but not observable with the data. As for Liteon ROM drives, I have seen errors that are too low and errors that are too high. Maybe it will not be the case with the AOpen but so far it does not look promising to me.

Still waiting for my 1648/aap to arrive. I have however just found a slightly worrying issue with this drive according to threads on the aopen forum: http://club.aopen.com.tw/forum/viewforum.asp?forumID=21
Lots of people are saying that the drive has trouble reading DVD-R's. Can any of you who have this drive shed any light on this? Do you think it could be due to poor quality burns being used by these people?

Still waiting for my 1648/aap to arrive. I have however just found a slightly worrying issue with this drive according to threads on the aopen forum: http://club.aopen.com.tw/forum/viewforum.asp?forumID=21
Lots of people are saying that the drive has trouble reading DVD-R's. Can any of you who have this drive shed any light on this? Do you think it could be due to poor quality burns being used by these people?

I can partly confirm this: My "el cheapo" fake Maxell discs (MXL-RG01) were readable in my Toshiba SD-M 1612 DVD-Rom. Some of these discs cause unrecoverable read errors after 3GB - and sometimes after 3.9 GB in the AOpen drive. The video playback stutters a bit.

You have to consider that these media are really of a very low quality. Any other medium works very well in this drive (even Princo 4x DVD-Rs work!) - and the performance is superior.

So if you don't use the cheapest DVDs, you should not have any problems.

Wow the -R problem can be decisive; I have quite a few cheap DVD-R discs, and I don't want to risc a no read on this DVD-ROM. How can it be the best dvdrom on the market today with such flaw? I guess I'll postpone the order of this drive, maybe till new firmware arise...

Got mine, waiting for me when I got home this evening. No problem reading both cheapish and better DVD-R's I've burnt with my LG 4040 @4X. In fact it will read a disk that no other previous reader I tried would (apart from my Panasonic DVD-S75 standalone player).

Attached are two disk quality tests, one of a burn I knew was not so good (cheapish media), one I knew was better (RITEK G04). You can clearly see the difference.

As has been mentioned above the drive reports errors on 32 ECC blocks and not the normal 8 of other drives (as is normally used in Kprobe scans). So PI errors and PI failures are upto 4 and 32 times higher than they would otherwise be. I was wondering whether Erik could say whether the quality score takes this into account in it's calculations. I seem to be getting what seem like very good scans but with quality scores as low as 10 or 20, even on pressed disks.

TDB host a 'hacked' RPC I (region free) version of the newest 1.07 firmware (I have flashed my drive with it, works fine). If you don't want to use hacked firmware, you can download the official firmware here.

Can this be changed? I mean, is it possible for the AOpen to collect data for 1 ECC block instead of 32 ECC blocks? If not, I guess we have to adjust our reference once and for all and forget about comparing with K's Probe scans. Unless ...

Most drives use a scanning resolution of 8 ECC, 32 ECC or 42 ECC blocks.
Only LiteOn DVD burners and a few other Mediatek-based drives use a sampling interval of 1 ECC.
I think it's unlikely that manufacturers will change the sampling interval of their drives just to make them comparable with LiteOn DVD burners because scanning at 1 ECC introduces several problems.

As has been mentioned above the drive reports errors on 32 ECC blocks and not the normal 8 of other drives (as is normally used in Kprobe scans). So PI errors and PI failures are upto 4 and 32 times higher than they would otherwise be. I was wondering whether Erik could say whether the quality score takes this into account in it's calculations. I seem to be getting what seem like very good scans but with quality scores as low as 10 or 20, even on pressed disks.

No, CD-DVD Speed doesn't do this yet so the scores at 32 ECC are indeed too low.
But this will be fixed in the next version

The problem is that you would get the average values while you need the maximum values. So the values would be much too low

Hm, not sure I understand this. If the PI values are 4 times higher and the PIF values are 32 times higher compared to the same disc scanned in K's Probe how can dividing PI and PIF by 4 and 32 give results that are too low? Excuse me if being thick-headed but I have had a hard day at work

I think he means the scores are coming out low the the quality score on the disk is not taking into account the 32 ecc setting and alwayes reads 0 even on good quality disks and this is what needs to be fixed on the next version.. I belive this keys off of the total errors found no max or average and these are higher becase of the block size...

The problem is that you would get the average values while you need the maximum values. So the values would be much too low.

I think this is the issue:

Consider part of a disk with 32 ECC blocks, four lots of 8 blocks. If these 32 blocks had PI failures of, say, 10, 12, 50, and 18 for each set of 8 blocks then a scan with a drive which scans at a resolution of 8 ECC blocks would return PIF of 10, 12, 50, and 18 for those four sets of 8 blocks. According to the no more han 4 PIF's per 1 ECC block standard, we would interpret the 50 as a fail as it is above this (8x4=32) standard. However as the aopen 1648 scans at 32ECC block level it would report (10+12+50+18=90) PIF's for this set of 32 ECC blocks which is below the (32ECCx4=128) standard and we would interpret as a pass. Dividing by 4 gives 90/4=23 which is again a pass against the 32 standard. I think this is what Erik means by dividing by 4 being equivalent to averaging and thus hiding a maximum and giving a lower value than is necessarily true.
Have I got this correct Erik?

Erik, I think the reason for the very high error rates at the beginning of the disc quality scan (even in a lot of 8x scans) is that the drive scans in CAV mode, instead of CLV. I don't know if the drive is actually able to read discs in CLV mode though, and if CLV could be added by Aopen via firmware (4x CLV mode for disc quality scanning would be ideal).

And as far as the 32 ECC blocks issue is concerned, it would be nice indeed to have comparable results. However, one should take the numbers with a grain of salt in both cases, Aopen 1648 / AAP and LiteOn, because both are inaccurate. More important than the numbers are the curves, and reducing the drive's influence on them.

Thanks packetloss
I've just bought 2 of these puppies, one for me, one for the kids.
Reads discs my NEC2500 could not.
Thanks again.
Des.
One question though, in Neroinfo it shows that the drive will not read DVD+r DL, I haven't any of this media atm but will this be upgraded in a future firmware flash. BTW I have flashed to 1.07.

Thanks packetloss
I've just bought 2 of these puppies, one for me, one for the kids.
Reads discs my NEC2500 could not.
Thanks again.
Des.
One question though, in Neroinfo it shows that the drive will not read DVD+r DL, I haven't any of this media atm but will this be upgraded in a future firmware flash. BTW I have flashed to 1.07.

You should not have any problems with DVD+R DL when the booktype of these discs is DVD-Rom. I don't know if it reads DVD+R DL with DVD+R DL booktype.

However, since almost all writers set the booktype to DVD-Rom automatically, it should not be a problem at all.